On 09/04/2012 04:59 PM, Joe Landman wrote:
> On 09/04/2012 12:54 PM, Lux, Jim (337C) wrote:
>> Hydrogen is cheaper than He and works even better. Just make sure you don't have any air leaks in (i.e. keep a bit of positive pressure). For the "server farm in a container" model, this would work just fine.. leaks would just float up into the atmosphere.
>>>> @ 300K
>> Air 26.2 mW/m*K
>> He 156.7
>> H2 186.9 !!!
>
> [singing to the tune of "you light up my life"]
>
I think you guys (Joe and RGB) missed the critical caveat Jim mentioned
in his first sentence about the "server farms in a container." I
understand this to mean the outdoor trailer container setup that Google
released in 2009, similar to the diagram in the following link:
http://asset2.cbsistatic.com/cnwk.1d/i/bto/20090401/Google_data_centers-4.jpg
Yes, Google does house these containers in a fairly basic building, but
there is no reason I can think of why it couldn't put them out in the
open and run all wires, etc, into the ground instead. I think they just
put them in a building for convenience to the maintainers, rather than
for some property of the building itself that would enable the
containers to work better.
I still agree (see my email 3 back now) that there are major concerns
with using hydrogen this way, but at massive scale and with massive
precautions you might be able to extract some nice power savings with
it. Maybe even enough to tolerate a few going sky high. Alas, my
physical sciences skills are way to weak to get a bound on what those
benefits might be.
Best,
ellis
> And you ...
> ... light up my server room
> ... You make it hot
>> And when sparks fly ...
> ... so do my servers in
> ... the ensuing explosion ...
>> (ok, I'll keep the day job ... sheesh!)
>>>> Ar 17.9
>> CH4 34.1
>>>> He also is hard to come by..
>>>>>>>>> Jim Lux
>>>> -----Original Message-----
>> From: Robert G. Brown [mailto:rgb at phy.duke.edu]
>> Sent: Tuesday, September 04, 2012 6:16 AM
>> To: Lux, Jim (337C)
>> Cc: Eugen Leitl; beowulf at beowulf.org>> Subject: Re: [Beowulf] Servers Too Hot? Intel Recommends a Luxurious Oil Bath
>>>> On Mon, 3 Sep 2012, Lux, Jim (337C) wrote:
>>>>> I'll bet they have to change it more often than that. This isnt
>>> something like a pole transformer.
>>>> Absolutely. Think of what you can do with a big vat of hot oil handy in the workspace. Buffalo Wings. French Fries. Chicken. Fish. The reason nobody does this is because OSHA prohibits it -- it is a huge health hazard. Not even Jolt Cola can keep you thin in a sedentary profession with your own personal deep frier as close as your server room. Although you do have to change the oil pretty often, as otherwise shrimp tails and bits of overcooked tempura crust gunk up the memory and CPU. Systems people were dying like pudgy little flies of advanced cardiovascular disease before the practice of using computers to heat deep fat was banned.
>>>> On a more serious note, one wonders why nobody has tried helium instead.
>> No, silly, not liquid helium, helium gas. The reason they fill windows with argon is that it has around 2/3 the thermal conductivity of air, and hence is a better insulator. This, in turn, is because it is more massive -- conductivity is tightly tied to mass and hence the speed of the molecules when they have kT sorts of energies.
>>>> Helium, OTOH, has six times the thermal conductivity of air, and is relatively inexpensive. The biggest downside I can think of is that it requires a pretty good seal and thick walls to keep the slippery little atoms from sliding right through to the outside, and of course the fact that systems techs would always be hitting up the helium tanks so that they could talk like Donald Duck. And you'd still have to refrigerate the outside of the systems units. But all of these things are still orders of magnitude easier than with oil, and even things like cooling fans work fine in Helium. Maybe there are other problems -- lower heat capacity to match its higher conductivity -- but it seems like it is worth an experiment or two...
>>>> rgb
>>>> Robert G. Brown http://www.phy.duke.edu/~rgb/>> Duke University Dept. of Physics, Box 90305 Durham, N.C. 27708-0305
>> Phone: 1-919-660-2567 Fax: 919-660-2525 email:rgb at phy.duke.edu>>>>>> _______________________________________________
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